Amith & wesson 66 & 19

Question
I recently acquired a smith pre dash model 19 and a pre dash model 66. I was doing research and a few  sources have said that although it is a .357 magnum because they are K frame guns they are not  meant to use them full time is this true? I Have also read that when using  the firearm with a .357 i should only use 158gr rounds. The sources  claimed that the forcing cone is weak at the bottom. any input to what I've read would be great. Thanks, Drew

Answer
As my bio indicated, my area is mostly in shooting. The firearms that I have intimate knowledge of are all in current military or LE circles.

158 grain projectiles will be easier on the gun than lighter ones, to be sure. It is certainly true that metallurgy has greatly improved since those guns were introduced, but it is also true that with better devices for measuring pressure, .357 Magnum ammunition does not generate the pressure it did when first introduced.

If it were my gun, I wouldn't worry about it that much, but why beat yourself or the gun up? Back when I owned a .357 I used to shoot .38's through it most of the time in practice, and save the .357 for only qual or serious training.